1. Field of the Invention
The present invention relates to an outboard motor.
2. Description of the Related Art
Outboard motors recently have been embedded with a number of electronic devices such as an ECU (Engine Control Unit) for controlling an engine and a digital meter for displaying a variety of information such as speed. Further, the outboard motors accommodate a battery cable for supplying electric power from a battery to the electronic devices and a wiring harness for transmitting electric signals among the electronic devices.
Meanwhile, an attempt to use a resin head cover instead of a metal head cover has been underway to reduce the weight of the outboard motor engine, as described in Japan Laid-open Patent Application Publication No. JP-A-2001-199392.
The aforementioned electronic devices normally radiate noise. Noise radiated from a given electronic device may have a negative impact on controls of the other electronic devices. Therefore, countermeasures are desirably executed for reducing the noise. In general, noise radiated from the electronic devices is reduced by grounding or shielding the electronic devices by metal members. Therefore, using a resin component for the engine goes against the noise reduction countermeasures although it is effective from the perspective of weight reduction of the engine.
Now, the outboard motor normally includes a resin casing for covering the engine. Therefore, a noise reduction effect cannot be expected in the outboard motor unlike a metal hood of an automobile.